Solar cells rely on silver to help generate electricity efficiently, but its rising cost and growing demand mean the renewable energy industry is keen to reduce its use – while not compromising performance.
Solar power may have become one of the world’s cheapest sources of renewable electricity, but an increasingly expensive precious metal is creating a challenge for the industry.
Silver, a material commonly associated with jewellery and electronics, plays an important role in helping solar cells generate electricity.
However, its rising price and growing demand are putting pressure on manufacturers, prompting researchers to investigate whether cheaper alternatives can do the same job.
At UNSW Sydney, Dr Ning Song and her research team, working closely with Scientia Professor Martin Green , are exploring ways to reduce the amount of silver used in solar cells, or potentially eliminate it altogether.
The challenge is not simply finding a cheaper material. Any alternative must also help solar panels generate electricity efficiently – and do so reliably for decades, without undermining the affordability and environmental benefits that have helped make solar power so attractive.
Why do solar panels need silver?
Solar panels generate electricity when sunlight hits photovoltaic (PV) cells, usually made from silicon. But producing electricity is only part of the process: that electricity also needs to be collected and transported out of the cell.
Silver performs this important function.
Solar cells contain extremely thin metal lines, called contacts, that collect the electricity generated within the cell. Silver is particularly well suited to this job because it conducts electricity exceptionally well and can be manufactured into fine lines using a relatively straightforward printing process.
These properties help solar cells generate electricity efficiently while minimising the amount of sunlight blocked by the metal contacts.
“Silver is used for the metal contacts that get the current out of the solar cells,” says Dr Song, a Senior Lecturer in UNSW’s School of Photovoltaic and Renewable Energy Engineering .
“It has very good conductivity and is easy to screen print. So silver has been one of the best for performance, but not necessarily moving forward for cost and sustainability.”
Why is silver becoming a problem?
Silver is expensive, and its price can fluctuate considerably. Recent price volatility has increased the pressure on manufacturers to reduce the amount used in each solar cell.
And when the price of silver rises, solar manufacturers face higher production costs.
Silver paste, which is used to form the electrical contacts, accounted for up to 30% of the cost of manufacturing a solar cell when silver prices peaked in early 2026, say industry analysts, although the share varies with cell technology, silver prices and paste consumption.
The rising cost of silver is one of the reasons that solar panel manufacturers are accelerating efforts to find alternatives, with researchers such as Dr Song vitally important in the process.
“In academia, we investigate the fundamental mechanisms behind how solar cells work, but we also develop new materials and manufacturing technologies to improve their performance and reduce costs,” she says.
“I think it’s a joint effort. Industry brings extensive manufacturing expertise and the ability to scale up technologies. By working together, we can combine scientific understanding with technological innovation to develop practical solutions for the solar industry.”
As well as the cost issue, silver is a finite resource, and growing demand from photovoltaics and other industries has raised questions about long-term supply.
Mining and processing silver also have environmental impacts, including energy consumption, land disturbance and waste generation. Reducing silver use could help ease pressure on supply and reduce some impacts associated with its extraction.
So the work of Dr Song and others in the field to find a potential alternative to silver in the production of solar cells is becoming ever more important.
What could replace silver?
Researchers are investigating several alternatives, including aluminium, nickel and copper. Each offers potential advantages, but none is a straightforward replacement.
Aluminium: a cheaper option with electrical challenges
Aluminium is significantly cheaper than silver and is already used in some solar-cell designs.
Aluminium is also used in established solar-cell metallisation processes, although its suitability depends on the contact structure and the processing conditions.
However, aluminium is less electrically conductive than silver, and the contact interface and firing process must be carefully controlled to avoid additional electrical losses.
Dr Song and colleagues are investigating ways to address these problems by adjusting the composition of aluminium pastes and optimising manufacturing conditions.
The UNSW team is studying how metal-paste formulations, contact interfaces and manufacturing conditions influence electrical losses in silicon solar cells. This work aims to identify practical ways to use less silver while maintaining cell performance.
“We are trying to reduce these losses by tuning the aluminium paste recipe and optimising the firing conditions,” she says.
The aim is to reduce silver use without sacrificing the performance of the finished cell. If successful, this could help manufacturers lower costs while maintaining the efficiency that makes solar panels commercially attractive.
In another study , researchers developed an aluminium paste that could reduce silver use and simplify the manufacturing process for advanced back-contact cells.
UNSW teams have demonstrated aluminium rear contacts in industrially relevant TOPCon solar cells can achieve 22.9% efficiency , compared with 23.7% for silver-contact reference cells. The result shows the potential of aluminium while highlighting the need to further reduce electrical losses.
Copper: good potential, but difficult to protect
Copper is another attractive alternative because it is much cheaper than silver while offering similarly strong electrical conductivity.
However, copper can create problems when used in silicon solar cells. It can move into the silicon and interfere with the processes that allow the cell to generate electricity.
“Copper can also oxidise, potentially affecting its electrical performance and long-term reliability,” says Dr Song.
One approach uses silver-coated copper particles to reduce the overall silver content while helping manage oxidation and contact performance. Long-term reliability and process compatibility remain important considerations.
Nickel: promising, with contact challenges
Nickel is also being investigated because it is relatively stable and already has established uses in semiconductor manufacturing.
However, nickel-based contacts can introduce electrical losses and other technical challenges.
In a recent study published in Solar Energy Materials and Solar Cells, Dr Song’s team, including PhD researcher Lizhi Sun and Scientia Professor Martin Green, investigated partially replacing silver with nickel in the rear contacts of industrial TOPCon solar cells. With a suitable nickel powder, replacing 10% of the silver powder by weight reduced rear-finger raw-metal costs by 6.8%, with an absolute efficiency decrease of just 0.024 percentage points.
“Replacing silver with nickel is not simply about using a cheaper metal. We need to consider how the nickel powder affects electrical contact performance, printability and the amount of paste consumed during manufacturing,” says Dr Song.
The researchers found that increasing the nickel content could increase paste consumption and largely offset the expected cost savings. Their findings highlight the importance of considering both material properties and manufacturing requirements when developing practical alternatives to silver.
Researchers are continuing to investigate nickel-based pastes and manufacturing processes to determine whether they can deliver the necessary performance and reliability.
No silver bullet
Dr Song says there is no single solution to the problem of replacing silver that will work for every solar cell.
“It’s really dependent on the cell structure,” Dr Song says. “It’s hard to say which material will ultimately prove the most suitable.”
Different solar-cell designs have different manufacturing requirements, meaning a material that works well in one technology may not be suitable for another.
Dr Song believes continued research in partnership with industry could enable substantial reductions in silver use, and potentially silver-free contacts in selected cell technologies, over the coming years. The pace will depend on manufacturing compatibility, performance and long-term reliability.
One of the biggest obstacles to that timeline is reliability.
Solar panels are expected to operate outdoors for approximately 25 to 30 years, meaning manufacturers must be confident that alternative contacts will withstand prolonged exposure to environmental conditions.
“Although other options may have passed testing in the lab, industry still needs confidence from outdoor testing and that data may not yet be available,” Dr Song says.
“We have to make sure the modules are reliable over the long term so they can work efficiently for many years.”
